Sequential motor operation under control of individual, fluid actuated, relieved pressure valves



2,607,197 DUAL, FLUID G. S. JOHNSON Aug. 19, 1952 SEQUENTIAL MOTOROPERATION UNDER CONTROL OF INDIV ACTUATED, RELIEVED PRESSURE VALVESFiled Aug. 6. 1949 @MMR Patented Aug. 19, 1952 SEQUENTIAL MOTOROPERATION UNDER CONTROL OF INDIVIDUAL, FLUID ACTU- ATED, RELIEVED`PRESSURE VALVES George S. Johnson, Grand HavenpMich., assignor to KellerTool Company, Grand Haven, Mich., a corporation of Michigan ApplicationAdrgust 6, 1949, Serial No. 108,876

The invention relates to fluid pressure operated tools, and moreparticularly to an automatic control mechanism therefor; and the primaryobject of the invention is to provide an improved form of controlmechanism including a normally balanced control valve with means of asimple character operative in response to the movement of a power drivenmember, such VYas the spindle of an associated tool, to effect anunbalancing of the valve whereby to initiate'the operation of the tool.

A further object is to provide for -th-el momentary imbalancing of thecontrol lvalve to -initiate the operation of thetool whereupon 'thevalve is restored to its normaloperative condi-'" tion. y

A further object is to provide Ia control''mecha-i nism comprising anormally balanced control valve and means for automatically unbalancingthe same including a spring biased poppet valve and a-dashpot typeactuator therefor.

'I'he objects of the invention thus generally set forth, together withother Aland ancillary advantages are attained by the constructionandarrangement shown by way of illustration in the accompanying drawing, inwhich:

Figure l is a schematic view showing the proved control mechanism asappliedto a drilling apparatus composed of two-tool units, one of whichis" initiated in operation toadvance its spindle in response to theretraction of the spindle of the other unit. i

Fig; 2 is a longitudinal sectional view taken approximately in the planeof line 2 2 of Fig. 1,'but on an enlarged scale, and illustrating theconstruction and mode of operation of the poppet valves `and the dashpotactuator'therefor. f Fig. 3 is a fragmentary sectional View, takensimilarly on line 3-3 of Fig. 1,sho\ving the poppet valve construction.

My invention is shown'for purposes of illustration as applied to thecontrol of a plurality of (herein two) tool units arranged for actuationby air -or other fluid under Ipressure, in an arrangement such that oneunit is initiated in operation to advance the tool spindle, as anincident to the retraction of the spindle of the other unit. The toolunits 'are of the type disclosed in Taylor application Serial No. 81,056and form per se no ,part of the presentinvefntion. Each comprises lacylinder 'I having :pistons 8 and 8 spaced apart o-n a rod 9 anddisposed upon opposite sides of a stationary abutment I0. An air motorII connected with the rod 9 is 'arranged to drive a tool spindle IIa.

v- ,5 claims. (ci. ca -97)y 2 The cylinder abutment I0 is provi-ded Withtwo ports I2 and I2 communicating respectively with the piston chambersformed at the forward and rear sides `of the abutment. As set forth insaid Taylor application, airn is supplied to the motor I Icoincidentally with the supply of air to the forward piston chamber t0advance the piston and vtherefor the tool spindle I Ia.

The supply and exhaust of air to and from each unit is under the controlof a valve I3 shown remote from the cylinder instead of being appli-eddirectly to the cylinder as in said Taylor application. The valve is ofthe balanced ytype and comprises a casing I4 (Fig. l) providing a main'valve chamber I5 to which air under pressure is constantly suppliedthrough an inlet port I6 connected by a line I'I to a suitableY rorconvenient source. In the present instance one wall of the chamber I5provides 'a seat for a slide 'valve' I8 connected with an actuatingplunger I9 and normally urged by a spring I9a against/its seat. The portI6 is located beyond thev range of movement ofthe valve so that iair isconstantly supplie-d to the chamber I5. 'I'he valve casing I 4 has threepassages 20, 2| and 22 opening into the casing thro-ugh the valve seat.Passage=20 is connected by la conduit 23 to cylinder port I2,andypassage 2| is connected .by a conduit 24 to cylinder port I2'.Passage 22 disposed between :passages 20 and 2l communicates with theatmosphere.

In general the arrangement is such that Ywhen the valve member I8occupies its right hand zpostion (see unit A) fair under pressure passesfrom the valve chamber through passage 20 and conduit `23 to'cylinderport I2 for delivery to the forward piston chamber so asto advance thetool spindle, 'and air from the'rear piston chamberescapes therefromthrough port I2 and conduit 24 to passage 2I and thence to 'exhaustpassage 22, the latter two passages being then connected by slide valveI8. When the valve is shifted to the left (see unit B) air is `deliveredfrom'the chamber I5 to passage 2| and thencev through conduit 24 tocylinder lport I2 for' de-"' livery' to the rear piston chamber'.Concurrently, air from the forward-piston chamber exhausts' through portI2, conduit 23, valve passagey'lb plunger le connected with the valve isprovided with two opposed pistons 2'5 and 26 respectively operating incontrol chambers 21 land 28 normally closed except for communicationwith the main pressure chamber I through small ports 29 and 3G in theresponsive :pistons Thus both chambers 21 and 28 are maintained underconstant pressure so that the plunger and therefore the valve isnormally in a state of balance. Shifting of the Valve in one directionor the other may be effected by unbalancing the valve, and this isaccomplished by the provision of poppet valves PI (Fig. 1) spring biasedtoward closed position and arranged for operation either manually orautomatically to establish communication between the respective controlchambers and the atmosphere.

These poppet valves may be of any suitable or preferred construction. Asherein shown, each valve I3 is equipped with a pair of manually op-.erable poppets, each comprising a tting 3l mounted in the valve casingland having a bore 32 communicating with one of the control chambers 21,28 (Fig. 3). Within the bore 32 is a spring biased valve member 33'operative to establish communication between the control chamber andthe atmosphere through an exhaust port 34 in the tting. It will beunderstood, of course, that the .port 34 and connecting passages have asubstantially greater effective karea than the ports 29, through whichpressure fluid is supplied to the chambers 21, 28. The valve member 33is formed upon the inner end of aplunger 35 having a stem 36 equippedwith an actuating head 31, the valve member being held in closedposition by a spring 38. It will be obvious that :by depressing the head31, the pressure in the control chamber will be relieved so as to causethe valve I8 to be shifted by the pre-ssure exerted thereon in theopposing control chamber.

In addition to or as an alternative to manual control by the poppetvalves PI provision is made for the automatic actuation of the controlvalves I3. I have herein shown by way of example the automatic operationof the main control valves I3 of tool units A and B in response to themovements of their respective spindles, and also the automatic advanceof tool unit B iii-response to the movement of some other power drivenmember such as the spindle of unit A so that unit B will be initiatedonoperation in timed relation to the movement of such member.

Referring then to Fig. 1, I have shown two poppet valves P2 and P3associated with the spindle of tool unit A, and a third poppet valve P4associated with the spindle of tool unit B. These poppet valves P2, P3and P4 are per se of the same construction as the valve PI abovedescribed, but instead of being mounted on the valve casing I4, each ismounted on a suitable stationary support on one or the other of the toolunits. Thus the valves P2 and P3 are mounted upon a pair of blocks 39connected by a rod 39A so as to be spaced apart in a direction parallelwith the axis of the unit A, at the rear end thereof, and thusalinedwith a dog 43 mounted on a rod 4I which projects rearwardly from thecylinder and constitutes an extension of the piston rod 9.

As shown in Fig. 2, the tting 3l of each of the poppet valves P2, P3`and P4 is threaded into a bore 42 in the supporting block with the head31 projecting toward one side of the block for engagement by the dog onthe piston rod extension 4I. In the case of unit A, the valve P2 isconnected by a conduit 43 to a bore opening into the control chamber 21of the associated vthe opening of poppet valve P4.

4 control valve I3, and valve P3 is similarly connected by a conduit 44with control chamber 28 of the main control valve associated with unitB. Valve P4 of unit B is connected by a conduit 45 with control chamber21 of the associated main control valve.

Assumingthat in the arrangement shown in Fig. 1 unit A is advancing andunit B is in condition to be advanced in response to the return of unitA to its initial position: Upon engagement of the dog 40 of unit A withpoppet valve P2, control chamber 21 is momentarily vented to theatmosphere to unbalance the associated main control valve and causeshifting of its valve member I8` to the left thereby uncovering passage2| and connecting passages 20 and 22. Air under pressure is thusdelivered through conduit 24 to the rear piston chamber of unit A toretract the spindle, and air from the forward piston chamber isexhausted through conduit 23, passage 20 and exhaust passage 22.

Upon the return of the spindle of unit A to its retracted position, dog40 engages poppet valve P3, venting control chamber 28 of the valve ofunit B tothe atmosphere, and causing valve member I8 of this unit toshift to the right. Thereupon air is delivered from the valve chamber I5through passage 2B and conduit 23 to cylinder port I 2,` therebyadvancing the spindle of unit B, the air in the rear piston chamberexhausting through conduit 24 and valve passages 2| and 22.

At the end of the advancing stroke of unit B puppet-valve P4 is actuatedto unbalance its valve I3 so as to effect retraction of the spindle; andat the end of such retracting movement, this unit comes to rest. thevalve I3 remaining in the retract position subject to operation inresponse to the retraction of unit A in the next cycle of the apparatus.Similarly, the valve I3 of unit A has remained in its retract position.To initiate a new cycle of the apparatus, unit A is advanced undermanual control by depressing the poppet valve PI to vent control chamber28 of the associated control valve I3.

It will be observed that the construction and arrangement employedrequires that the poppet valves be operated only momentarily, just longenough to effect the unbalancing of the main control valves. In the caseof poppet valves P2 and P4,` the valves I3 associated therewith, afterbeing opened by their respective dogs are closed in the ensuing reversalof the units; but in the case of poppet valve P3, there is no ensuingmovement of the spindle of unit A following the opening of the valve bydog 40 inasmuch as this valve is utilized to control unit B upon thetermination of the retracting movement of unit A. Thus the opening ofpoppet valve P3 would normally this, dog 40 of unit A is provided withan actuator 46 (Fig. 2) operating upon the principal of a dashpot toeffect closure of poppet valve P3 after a short time interval. As shown,the actuator 46 comprises a cylinder 46a having a plunger 41 equippedwith a loose fitting piston 48. The cylinder is made in two sectionsscrew threaded together and suitably mounted on the Vdog 40, the latterbeing in the present instance in the formof -a lfiatplate adjustablymounted on the extension 4| o fqtlie jpiston'rod 9. The cylinder 46a, isiilled withA oil for: other suitable .liquid and theplunger'll'lljprojectsrom opposite sides of the dog plate, the cylinder beingequipped withv suitable packing rings toi prevent 4the escape of oil..The parts are so proportioned that upon the retraction of the spindle ofunit A, the plunger engages with poppet valveP3, its movement relativeto the cylinder being suiciently retarded by the oil contained thereinto cause momentary opening of the valve. However, because '.of. theloose fit of the piston in the cylinder, oil'on'one side of the pistonescapes slowly to the other side under the force of the poppet valvespring 38 so that after a lapse of a predetermined time interval thevalve closes and thereby closes control chamber 28 of the valve of unitB to condition the same for operation under the control of pop- Detvalve P4.

It should be observed that the dashpot actuator 45 is constructed with aview to the operation of the poppet valve P3 in the return movement ofthe spindle of unit A, which occurs at high speed as set forth in Taylorapplication Serial No. 81,050, whereas the actuation of poppet valve P2occurs at the end of the feeding movement of a spindle and therefore ata very slow speed..

Accordingly, upon engagement of the plunger 41 of actuator 46 withpoppet valve P2, the rate of movement of the dog 4B is so slow as topermit relative shifting movement of the plunger 41 in the cylinder 45aso that opening of the poppet valve occurs at the end of such relativemovement between the parts of the actuator. Accordingly, the plunger ispositioned in its cylinder so as to be conditioned for the actuation ofpoppet valve P3 at the end of the rapid return stroke of the spindle ofunit A.

I claim as my invention:

l. In a machine tool comprising a tool unit having a tool spindle, fluidpressure operated spindle reciprocating means including a cylinder and apiston therein and a control system governing the supply of pressurefluid to said cylinder to advance said spindle comprising a valve deviceand a pair of control chambers normally under pressure to hold saidvalve device against movement, and means for shifting said valve deviceto initiate the operation of the pressure iiuid actuated means toadvance the tool spindle in-- cluding a poppet valve associated with oneof said control chambers having a spring biasing it toward closedposition and acting to prevent the escape of pressure fluid from saidone control chamber, and a dashpot actuator operable by said powerdriven member for opening said poppet valve momentarily, said actuatorcomprising cylinder and plunger elements coacting upon a rapid movementof one of the elements by said member to transmit an actuating force tothe other element to open the poppet valve but yieldable relative toeach other under the action of said biasing spring to effect closure ofthe poppet valve.

2. In a machine tool comprising, in combination, a tool unit having acylinder and a piston actuator, means controlling the admission ofpressure fluid to said actuator cylinder to advance the pistoncomprising a control device having an actuating plunger and a pair ofcontrol chambers normally under pressure and holding said plungeragainst movement, and means for venting one of said control chambers tothe atmosphere to effect movement of the plunger by the pressure in theother chamber including a valve, a spring 6. urging said-valve-to'closedposition, and a dash'- pot 'actuator operative in?'response'toftheadvance of:v said piston to v`open "said valve,` saidactuatorfincluding a cylinder and piston device effective. to delayreclosure ofsaid valve by said spring for aipredeterminedv time intervalf ollowing the. opening of the valve. l

.-3. In..a machine tool` comprising a'plurality ofit'o'ol units eachhaving atool spindle and iiuid pressure operated means for reciprocating'the spindle including a cylinder and piston actuator, a `source lof.fluid .under pressure, 'and ka -control system'forgoverning the supply`and exhaustjof pressure fluid to and from the actuator cylinderscomprising, in combination, a control valve associated with each unitincluding a casing having opposed control chambers connected to receivea restricted supply of uid under pressure from said source, a movablevalve member projecting into said chambers and presenting substantiallyequal eiective areas in each chamber, said member being shiftedoutwardly from either chamber by the pressure of the fluid thereinresponsive to the venting of the other chamber to the atmosphere, a pairof poppet valves associated with each actuator cylinder operable to ventrespective ones of said chambers to initiate forward and returnmovements of the associated spindles', and a valve actuator operable byone of said spindles on retraction for actuating the valve forinitiating forward movement of the other spindle. 4. In a machine toolcomprising a plurality of tool units each having a tool spindle andfluid pressure operated means for reciprocating the spindle including acylinder and piston actuator, a source of fluid under pressure, and acontrol system for governing the supply and exhaust of pressure fluid toand from the actuator cylinders comprising, in combination, a controlvalve associated with ea-ch unit including a casing having opposedcontrol chambers connected to receive a restricted supply of fluid underpressure from said so-urce, a movable valve member projecting into saidchambers and presenting substantially equal effective areas in eachchamber, said member being shifted outwardly from either chamber by thepressure of the iiuid therein responsive to the venting of the otherchamber to the atmosphere, a pair of poppet valves associated with eachactuator cylinder, each of said valves being biased to a closed positionand operative when shifted to open position to vent respective ones ofsaid chambers to initiate shifting of said valve member and consequentforward and return movements of the associated spindles, and a valveactuator operable in the retraction of one of said spindles to open thepoppet valve for initiating forward movement of the other spindle, saidvalve actuator being operative to allow the opened poppet valve to closeafter a predetermined interval.

5. In a machine tool comprising a plurality of tool units each having atool spindle and fluid pressure operated means for reciprocating thespindle including a cylinder and piston actuator, a source of iluidunderr pressure, and a control system for governing the supply andexhaust of pressure fluid to and from the actuator cylinders comprising,in combination, a control valve associated with each unit including acasing having opposed control chambers connected to Areceive arestricted supply of fluid under pressure from said source, a movablevalve member projecting into said chambers and presenting substantiallyequal eiective areas in each chamber, said member being shiftedoutwardly from either chamber by the pressure of the iiuid thereinresponsive` to the venting of the other chamber to the atmosphere, apair of poppet valves associated with each actuator cylinder, each ofsaid `valves being biased to a closed position and operative whenshifted to open position to vent respective ones of said chambers toinitiate shifting of said valve member and consequent forward andreturn-movements of the associated spindles, valve actuating meansoperable in the retraction of one of said spindles to actuate the poppetvalve for initiating forward movement of the other spindle, saidactuating means including an element movable with said one spindle toshift the poppet valve to open position, and a dashpot device associatedwith REFERENCES CITED The followingreferences are of record inthe fileof this patent:

UNITED STATES PATENTS Number Name Date 1,787,781 Galloway Jan. 6, 19312,176,008 Hoyt 0G12, 10, 1939

